Semiconductor capacitors are used in a variety of applications including operational amplifier frequency compensation, conversion of analog signals to digital signals, modulation of logic output voltage rise and fall times, etc. Fabrication of semiconductor capacitors using monolithic integrated circuit fabrication techniques is well known in the semiconductor art. A particularly useful type of semiconductor capacitor is the voltage variable capacitor, more commonly referred to as a varactor. Varactors are used in a variety of applications such as the electronic tuning of oscillators and the mixing or the generation of harmonics of electrical signals. Due to the difficulty in fabricating varactors having a low series resistance, a desirable change in capacitance for a given change in voltage, and a low DC leakage current using high performance integrated circuit processes, these devices are typically manufactured as discrete components having an electrical contact on each side of a semiconductor substrate.
Accordingly, it would be advantageous to have a method of manufacturing a varactor that is readily incorporated into a high performance integrated circuit process and that provides a low series resistance and a desirable change in capacitance for a given change in voltage.